1. Technical Field
The present disclosure relates to a song accompaniment apparatus and method, and more particularly, to a song accompaniment apparatus and method for eliminating voice signals from a mixture of music and voice signals.
2. Description of the Related Art
Song accompaniment apparatuses having karaoke functions are widely used for singing and/or amusement. A song accompaniment apparatus generally outputs (e.g., plays) a song accompaniment to which a person can sing along. Alternatively, the person can simply enjoy the music without singing along. As used herein, the term “song accompaniment” refers to music without voice accompaniment. In such song accompaniment apparatuses, a memory is generally used to store the song accompaniments which a user selects. Therefore, the number of song accompaniments for a given song accompaniment apparatus may be limited by the storage capacity of the memory. Also, such song accompaniment apparatuses are generally expensive.
Karaoke functions can be easily implemented for compact disc (CD) players, digital video disc (DVD) players, and cassette tape players outputting only song accompaniment. Users can play their own CDs, DVDs, and cassette tapes. Similarly, karaoke functions can also be easily implemented if voice is eliminated from FM audio broadcast outputs (e.g., from a radio) such that only a song accompaniment is output. Users can play their favorite radio stations.
Acoustic signals output from CD players, DVD players, cassette tape players, and FM radio generally contain a mixture of music and voice signals. Technology for eliminating the voice signals from the mixture has not been perfected yet. A general method of eliminating voice signals from the mixture includes transforming the acoustic signals into frequency domains and removing specific bands in which the voice signals are present. The transformation to frequency domains is generally achieved by using a fast Fourier transform (FFT) or subband filtering. A method of removing voice signals from a mixture using such frequency conversion is disclosed in U.S. Pat. No. 5,375,188, filed on Dec. 20, 1994.
However, since some music signal components are included in the same frequency bands as voice signals, in the range of several kHz, some music signals are lost when those frequency bands are removed, thereby decreasing the quality of the output accompaniment. To reduce the loss of music signals from the mixture, an attempt has been made to detect a pitch frequency of the voice signals and remove only a frequency domain of the pitch. However, since it is difficult to detect the pitch of the voice signals due to the influence of the music signals, this approach is not very reliable.